PLOS on Tuesday published a new collection, titled, “Measuring Coverage in Maternal, Newborn, and Child Health,” “which presents innovative assessments of the validity of measuring population coverage for interventions in this field,” according to the collection’s table of contents, which adds, “This collection of original research articles and reviews shows that while some indicators can be measured accurately, others may not provide valid results and therefore need further investigation and development” (5/7). In an editorial accompanying the collection, Jennifer Bryce, who assisted in preparing the collection, “explains why measuring coverage of maternal, newborn, and child health interventions matters and what we can learn from the new PLOS collection” (5/7). “Rigorous measurement of the proportion of women and children in need of life-saving interventions who actually receive them remains a challenge, which is why the new collection … from PLOS Medicine is so timely,” Mariam Claeson and Wendy Prosser of the Bill & Melinda Gates Foundation, write in the foundation’s “Impatient Optimists” blog (5/7).